1. Field of the Invention
The present invention is related to a method of establishing links between contact information according to data validity of elementary files stored in smartcards, and more particularly, to a method of establishing links between contact information according to the correctness of the relationship between an index administration phone book elementary file and an abbreviated dialing numbers elementary file stored in smartcards.
2. Description of the Prior Art
Subscriber identity module (SIM) card is a smartcard that securely stores the international mobile subscriber identity (IMSI) used to identify and authenticate subscribers, short message service (SMS) data and contact information on mobile telephony devices. The hardware structure of a SIM card includes a central process unit (CPU), read-only memory (ROM), random access memory (RAM), electrically erasable programmable read-only memory (EEPROM), and an input/output (I/O) circuit. The hierarchical logic data structure of a SIM card includes 3 types of files: elementary file (EF), dedicated file (DF) and master file (MF).
The elementary files may adopt 3 main types of data structures for storing different types of data: transparent, linear fixed and cyclic. A transparent elementary file defines the data that is managed as a stream of bytes, which are addressed by an offset coming from the start of the file. A linear fixed elementary file or a cyclic elementary file is the data grouped into records, which is a block of bytes with a pre-defined size.
According to the 3rd Generation Partnership Project (3GPP) specification TS 31.102, the dedicated file DFPHONEBOOK contains all elementary files associated with the phone book, such as a phone book reference file elementary file EFPBR and other elementary files listed in the following table.
TABLETypeNameType 1Type 2Type 3EFAASXEFADNXEFANRXXEFEMAILXXEFEXT1XEFGASXEFGRPXEFIAPXEFPBCXEFSNEXXEFUIDXEFCCP1X
EFAAS represents an additional number Alpha string elementary file (Type 3). EFADN represents an abbreviated dialing numbers elementary file (Type 1). EFANR represents an additional number elementary file (Type 1 or Type 2). EFEMAIL represents an electronic mail elementary file (Type 1 or Type 2). EFEXT1 represents an extension1 elementary file (Type 3). EFGAS represents a grouping information Alpha string elementary file (Type 3). EFGRP represents a grouping file elementary file (Type 1). EFIAP represents an index administration phone book elementary file (Type 1). EFPBC represents a phone book control elementary file (Type 1). EFSNE represents a second name entry elementary file (Type 1 or Type 2). EFUID represents a unique identifier elementary file (Type 1). EFCCP1 represents a capability configuration parameters 1 elementary file (Type 3).
In the phone book reference file elementary file EFPBR, the first file ID in the first record indicated using constructed Tag ‘A8’ is called a master EF. File IDs indicated using constructed Tag ‘A8’ correspond to a Type 1 EF. File IDs indicated using constructed Tag ‘A9’ correspond to a Type 2 EF. File IDs indicated using constructed Tag ‘AA’ correspond to a Type 3 EF. A Type 1 EF and a master EF contain the same number of records, and each record in the Type 1 EF is mapped to a corresponding record in the master EF on a one-to-one basis. A Type 2 EF contains fewer records than and a master EF, and each record in the Type 2 EF is linked to a corresponding record in the master 1 EF by a pointer indicated in the Type 1 index administration phone book elementary file EFIAP. Each record in a Type 3 EF is linked to a corresponding record in the master EF by a record identifier with a record of the phone book reference file elementary file EFPBR.
Assume that two entries associated with a specific contact are stored in the phone book of a SIM card, wherein the phone number of the specific contact is stored in the Type 1 abbreviated dialing numbers elementary file EFADN and the electronic mail of the specific contact is stored in the Type 2 Email elementary file EFEMAIL. The records of the Type 2 electronic mail elementary file EFEMAIL are linked to corresponding records of the Type 1 abbreviated dialing numbers elementary file EFADN by corresponding pointers indicated in the Type 1 index administration phone book elementary file EFIAP. When a user deletes the entries associated with the specific contact, the prior art method only erases corresponding data in EFADN and EFEMAIL without handling EFIAP. Therefore, an incorrect link still remains between a valid pointer of EFIAP and invalid data of EFADN or EFEMAIL. In the prior art, the mobile device may display blank contact information after the user deletes entries associated with the specific contact, thereby causing confusion and inconvenience to the user.